1. Field of the Invention
The present invention is directed to an optical switch and, more particularly, to a switch that switches an optical beam from an input port to an output port without converting the signal to electrical form by the use of one or more optical phase changing spatial light modulators (SLMs).
2. Description of the Related Art
Today""s packet switched communication networks, such as the Internet, are implemented using fiber optic technology where a modulated laser beam is transmitted down an optical fiber or glass wave guide. Switching between fibers within the network is typically performed by converting the light signal into an electrical signal, performing the switching function on the electrical signal and then converting the electrical signal into a light signal. These conversion operations are slow and expensive.
What is needed is a switch that switches the light beam between input and output fibers optically directly without converting the signal into electrical form.
A direction of a laser beam can be changed via a number of different techniques, including reflecting the beam from a mirror that can be rotated. However, rotating a mirror is slower than desired for many switching operations.
What is needed is an optical switch that will switch beam directions faster.
It is an object of the present invention to perform optical switching for an optical network by changing the relative-phase of individual portions of the cross section of a wave front of a beam.
It is another object of the present invention to use one or more phase spatial light modulators (SLMs) to perform optical switching.
It is another object of the present invention to use phase spatial light modulators that include an array of phase shifting elements in such a manner that each of the phase shifting elements moves a maximum distance of about one half of the wavelength of light.
It is an additional object of the present invention to use phase spatial light modulators that include an array of phase shifting elements in such a manner that the area of the phase shifting mirror or element is smaller than the cross section of the portion of the beam of light the element is modulating.
It is also an object of the present invention to provide optical routers and cross connect switches which perform switching of one or more optical beams between optical fibers using phase spatial light modulation.
The above objects can be attained by a system that includes one or more phase spatial light modulators as optical switching elements in an optical switching system. One or more input light beams are deflected by one or more input optical deflectors. The beam can be further deflected by one or more output optical deflectors. Each deflector changes the direction of the light beam by changing the phase of the beam wave front by displacing pixel reflectors in a direction essentially perpendicular to the beam axis and relative to each other.
These together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.